Radar sensor system and method for operating a radar sensor system

ABSTRACT

A radar sensor system and a method for operating a radar sensor system. The radar sensor system includes: at least one first sub-sensor system and a second sub-sensor system, each for generating sensor data, each sub-sensor system including an antenna array including at least one receiving antenna and at least one transmitting antenna; a control device, by which each sub-sensor system is independently transferrable from a normal operation into a silent operation; and a data fusion device, which is designed to fuse the sensor data exclusively of the sub-sensor systems during the normal operation with one another for generating output data.

FIELD

The present invention relates to a radar sensor system, in particular,for a motor vehicle or in a motor vehicle, and to a method for operatinga radar sensor system, in particular, for a motor vehicle or in a motorvehicle. The motor vehicle is preferably a passenger car or a truck.

BACKGROUND INFORMATION

Radar sensors are increasingly used in a plurality of applications. Inparticular, in vehicles, such as automobiles, additional sensors are toassume a growing number of tasks, in particular, in the context ofautomated or assisted driving. In addition to the performance of a radarsensor during normal operation, additional requirements exist withregard to availability of the sensor.

When a radar sensor, in existing driver assistance applications, showedan error, a consolidated state, or also an “emergency operation,” wasfrequently achieved by the entire radar sensor terminating thecommunication to the outside, for example a communication with a bus,e.g., a vehicle bus. When here and hereafter mention is made of errors,this shall, in particular, be understood to mean so-called E/E errorsaccording to the ISO 26262 standard.

For example, German Patent Application No. DE 10 2014 213 171 A1describes a system for autonomous vehicle guidance and a correspondingmotor vehicle.

Considerable requirements exist for radar sensors with respect tokeeping the probability for a failure low. According to the ISO 26262standard, the probability for a failure of a component is determined ina unit named FIT (“failure in time”), 1 FIT denoting one error in 10⁹hours, or 10⁻⁹ errors per hour.

In the case of the ASIL-B or ASIL-C (Automotive Safety Integrity Level,also defined in ISO 26262) safety levels, for example, a component isallowed to have a maximum of 100 FIT, components not being taken intoconsideration which are in a silent operation, in which the component nolonger carries out any communication whatsoever and is thus in a safestate. In this silent operation, the component thus cannot result in orcontribute to unfavorable or undesirable decisions.

For example, a choke of a switching regulator is indicated having 38FIT. In general, at least two such chokes are used to operate amicrocontroller, whereby a budget of 100 FIT would already largely beexhausted at a rate of 76%, even if all other components had a FIT valueof 0.

SUMMARY

It is desirable to provide a radar sensor system and a method foroperating a radar sensor system, which allow a reliable output of radardata even if errors, unexpected events and unknown states occur.

The present invention provides a radar sensor system and a method.

In accordance with an example embodiment of the present invention, aradar sensor system is provided, including: at least one firstsub-sensor system and a second sub-sensor system, each for generatingsensor data, each sub-sensor system including an antenna array includingat least one receiving antenna and at least one transmitting antenna; acontrol device, by which each sub-sensor system may be independentlytransferred from a normal operation into a silent operation; and a datafusion device, which is designed to fuse the sensor data exclusively ofthe sub-sensor systems during normal operation with one another forgenerating output data.

In other words, it may be provided that in each case only those sensordata whose sub-sensor systems are in the normal operation, i.e., havenot been transferred into the silent operation, contribute to thegeneration of the output data. In other words, the silent operation maybe defined, e.g., in that the sensor data of sub-sensor systems in thesilent operation do not contribute to the generation of the output data.The normal operation of each sub-sensor system can accordingly bedefined in that the sensor data of the sub-sensor system in the normaloperation are used for generating output data, in particular, are fusedwith the sensor data of the other sub-sensor systems in the normaloperation.

It may be provided that one or multiple sub-sensor system(s) may betransferred from the silent operation back into the normal operationwhen certain conditions are present, in particular, that one or multiplesub-sensor system(s) may be switched back and forth between normaloperation and silent operation. When a sub-sensor system has beentransferred from the silent operation back into the normal operation,the sensor data of this sub-sensor system will accordingly also be usedagain to generate the output data, e.g., be fused with the sensor dataof other sub-sensor systems in the normal operation.

The emergency operating mode of a radar sensor system thus represents aconsolidated state in which the sensor data of this sub-sensor systemcannot have any negative effects on the output data, i.e., on theoverall result of the radar sensor system. In this way, for example, aFIT value of considerably less than 100 may be achieved for the radarsensor system in that the sub-sensor systems in fact have higher FITvalues, but they are disregarded in the overall consideration since eachsub-sensor system, in the silent operation, no longer has any effect onthe output data.

The control device may, in particular, be designed in such a way that itidentifies errors in the individual sub-sensor systems, or receives asignal indicating an error in individual sub-sensor systems, andtransfers each sub-sensor system into the silent operation in which itidentified an error or in which an error was indicated. The controldevice may also be designed in such a way that it establishes that anerror no longer occurs in a sub-sensor system, or receives acorresponding signal which indicates this, and, based thereon, transfersthe corresponding sub-sensor system back into the normal operation.

According to the present invention, an availability of output data ofthe sensor system may be considerably increased. A failure rate of theoverall radar sensor system may already be considerably reduced even ifonly two sub-sensor systems are present. Such a total failure of theradar sensor system may namely be present at the most when an erroroccurs which affects all sub-sensor systems, or when all sub-sensorsystems are affected by errors independently of one another, which isunlikely.

The reduced failure rate overall results in a high availability of allthose output data which may already be detected by a single sub-sensorsystem. In the best case, the radar sensor system will use the sensordata of all sub-sensor systems, in particular, fuse these with oneanother, for generating the output data. However, even in an error, theradar sensor system will still use the sensor data of N−1 sub-sensorsystems to generate the output data in the case of a radar sensor systemincluding N sub-sensor systems and an error in one of these N sub-sensorsystems.

An operation of the radar sensor system in which not all N sub-sensorsystems are presently used for generating the output data may bereferred to as an emergency operation of the radar sensor system. Duringthe emergency operation, the radar sensor system may possibly not reachthe full performance, but still a considerable portion, e.g., 50%, ofthe full performance. Such an emergency operation may be used, forexample, to bring the vehicle or the device equipped with the radarsensor system into a secured state.

For example, a vehicle including such a radar sensor system may besteered to a halt along the roadside or in a repair shop. However, it isalso possible that a vehicle including the radar sensor system iscontrolled to carry out a rapid halt on the instantaneous traffic lane.The respective secured state into which the device or the vehicleincluding the radar sensor system is transferred may depend on thenumber of failed sub-sensor systems, i.e., transferred into the silentoperation. In other words, the secured state may encompass a measurewhich takes effect in a shorter term, or may be sought more quickly, themore of the sub-sensor systems were transferred into the silentoperation.

The present invention thus also provides a device, in particular, avehicle, which includes the radar sensor system according to the presentinvention and which is transferrable into a secured state, e.g., issteerable into a safe position, as a function of the output data of theradar sensor system.

Furthermore, in accordance with an example embodiment of the presentinvention, a method is provided, including the steps: receiving sensordata of a first sub-sensor system of a radar sensor system; receivingsensor data of a second sub-sensor system of the radar sensor system;transferring at least one of the sub-sensor systems, independently ofthe other sub-sensor systems, from a normal operation into a silentoperation; fusing the sensor data exclusively of those sub-sensorsystems which are in the normal operation for generating output data;and outputting the generated output data.

Further specific embodiments and refinements are derived from thedescription with reference to the figures.

According to one preferred refinement of the present invention, theradar sensor system includes a clock generator, which provides a sharedclock signal to the sub-sensor systems. The fusion of the sensor datafor generating the output data advantageously takes place using theclock signal. In this way, a synchronization of the sensor data may beachieved or improved.

Accordingly, the example method according to the present invention mayalso encompass a step of providing a shared clock signal to thesub-sensor systems, and provide that the fusion of the sensor data takesplace using the shared clock signal.

According to another advantageous refinement of the present invention,the data fusion device is designed to fuse the sensor data generated bythe sub-sensor systems at a raw data-near level.

In the scientific paper by Hall, D. L. and Llinas, J.: “An introductionto multisensor data fusion,” in “Proceedings of IEEE Vol. 85, 1997,” pp.6-23, a system for classifying data levels is described. Accordingly,the raw sensor data may be fused with one another during the so-called“data fusion” prior to further signal processing steps, such as duringthe noise suppression with the aid of beamforming. An extraction ofunambiguous features takes place prior to the fusion during theso-called “feature fusion.” The newly combined feature vectors aresubsequently further processed, e.g., in an audiovisual speechrecognition in which the acoustic and visual feature vectors arecombined, to achieve acceptable recognition rates, even in loudsurroundings or in the case of disrupted channels, by combining speechsounds and lip movements. During the so-called “decision fusion,” thecombination only takes place after all signal processing and patternrecognition steps have been carried out.

According to another advantageous refinement of the present invention,the data fusion device is designed to fuse the sensor data generated bythe sub-sensor systems at a raw data level or on a spectra level.

According to another advantageous refinement of the present invention,the control device is designed as a multitude of control units.Advantageously, each sub-sensor system is assigned at least one of thecontrol units for transferring the particular sub-sensor system into thesilent operation.

According to another advantageous refinement of the present invention,the control units are designed as microcontrollers.

According to another advantageous refinement of the present invention,the data fusion device includes a data interface between at least two ofthe multitude of control units.

According to another advantageous refinement of the present invention,the control device includes a central control unit for at least two ofthe sub-sensor systems or is made up of such a central control unit forall sub-sensor systems.

According to another advantageous refinement of the present invention,the antenna arrays of at least two sub-sensor systems are situatedpoint-symmetrically, axially symmetrically and/or rotation-symmetricallywith respect to one another.

According to another advantageous refinement of the present invention,each sub-sensor system includes a dedicated independent voltage supplyunit, which is feedable electrical energy via a shared plug connector ofthe radar sensor system.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in greater detail hereafter based onthe exemplary embodiments shown in the schematic figures.

FIG. 1 shows a schematic block diagram of a radar sensor systemaccording to one specific embodiment of the present invention.

FIG. 2 schematically shows a detail of a radar sensor system accordingto one possible specific embodiment of the present invention.

FIG. 3 shows a schematic block diagram of a possible specification of anelectronics architecture of a radar sensor system according to FIG. 1and/or FIG. 2 .

FIG. 4 shows a schematic flow chart to explain a method for operating aradar sensor system according to one further specific embodiment of thepresent invention.

In all figures, identical or functionally equivalent elements anddevices are denoted by the same reference numerals, unless indicatedotherwise. The numbering of method steps is used for the sake of clarityand is, in particular, not intended to imply a certain chronologicalsequence, unless indicated otherwise. In particular, multiple methodsteps may also be carried out simultaneously.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 shows a schematic block diagram of a radar sensor systemaccording to one specific embodiment of the present invention.

As is apparent from FIG. 1 , radar sensor system 100 includes at leastone first sub-sensor system 10 and a second sub-sensor system 20, eachfor generating sensor data. Each sub-sensor system 10, 20 includes anantenna array 13, 23 including at least one respective receiving antennaand at least one respective transmitting antenna. FIG. 1 shows thatfirst sub-sensor system 10 includes an antenna array 13, and that secondsub-sensor system 20 includes an antenna array 23. It shall beunderstood that radar sensor system 100 may also include more than twosub-sensor systems 10, 20, for example, three, four, eight or even moresub-sensor systems 10, 20.

As will be described hereafter, in particular, symmetrical arrangementsof antenna arrays 13, 23 of the individual sub-sensor systems 10, 20with respect to one another are preferred. In this way, preferably evennumbers, particularly preferably divisible by four, of sub-sensorsystems 10, 20 are used, so that antenna arrays 13, 23 of sub-sensorsystems 10, 20 may be situated with respect to one another according toone mirror symmetry or even two mirror symmetries.

Radar sensor system 100 furthermore includes a control device 50, bywhich each sub-sensor system 10, 20 is transferable from a normaloperation into a silent operation independently of any other sub-sensorsystem 10, 20.

Control device 50 is also shown schematically in FIG. 1 , in the form ofa single block. In several particularly advantageous specificembodiments, control device 50 is made up of a multitude of individualcontrol units, which are separated from one another and of which atleast one is assigned to each sub-sensor system 10, 20. Such specificembodiments are described in greater detail hereafter by way of examplewith reference to FIG. 2 .

Radar sensor system 100 furthermore includes a clock generator 60, whichprovides a shared clock signal 71 to sub-sensor systems 10, 20.

A data fusion device 30 of radar sensor system 100 is coupled tosub-sensor systems 10, 20 in such a way that the sensor data generatedby the sub-sensor systems may be fused with one another for generatingthe output data of radar sensor system 100. Data fusion device 30 isdesigned and configured to fuse the sensor data with one anotherexclusively of those sub-sensor systems 10, 20 which are in the normaloperation, i.e., which are presently not transferred into the silentoperation.

If radar sensor system 100 is thus in the best case, i.e., in a state inwhich all sub-sensor systems 10, 20 function error free, the sensor dataof all sub-sensor systems 10, 20 are fused with one another with the aidof data fusion device 30. If, however, radar sensor system 100 is in anemergency operation, i.e., if at least one sub-sensor system wastransferred into the silent operation, the sensor data of sub-sensorsystems 10, 20 transferred into the silent operation are not fused withthe sensor data of the other sub-sensor systems 10, 20.

This may be achieved, for example, by a sub-sensor system 10, 20, whichwas transferred by control device 50 into the silent operation, nolonger providing its sensor data to data fusion device 30. As analternative or in addition, control device 50 may inform data fusiondevice 30 via all those sub-sensor systems which are presentlytransferred into the silent operation and/or which have ever beentransferred into the silent operation. Data fusion device 30 may bedesigned in such a way that, during the generation of the output data,it does not take those sensor data which data fusion device 30 receivesfrom sub-sensor systems 10, 20 indicated by control device 50 as havingbeen transferred into the silent operation into consideration, i.e., inparticular, for example, does not fuse these with other sensor data.

As a further alternative, it may be provided that each sub-sensor system10, 20 which was transferred into the silent operation communicates thisto data fusion device 30 itself, for example as part of the sensor dataor as a status signal attached to the sensor data which are beingtransmitted to data fusion device 30. Data fusion device 30 may thus bedesigned in such a way that sensor data denoted in such a way are nottaken into consideration by data fusion device 30.

Data fusion device 30 may be designed separately from sub-sensor systems10, 20. In several advantageous specific embodiments, data fusion device30, however, is designed and situated in a distributed manner and, inaddition to a respective processing unit of a respective sub-sensorsystem 10, 20, also includes data lines between the individualsub-sensor systems 10, 20, preferably direct data links between theindividual sub-sensor systems 10, 20.

It is also possible that data fusion device 30 is integrated intocontrol device 50. Control device 50 may thus function as a centralcontrol device, with which sub-sensor systems 10, 20 are advantageouslypermanently in contact: control device 50 may transfer each sub-sensorsystem 10, 20 into the silent operation at any time. For this purpose,control device 50 advantageously receives data continuously, or at leastregularly, for example the sensor data of the respective sub-sensorsystems 10, 20, based on which control device 50 determines whether therespective sub-sensor system 10, 20 is able to remain in the normaloperation, or whether it is transferred into the silent operation (or,conversely, whether a sub-sensor system 10, 20 transferred into thesilent operation is transferred back into the normal operation).

The use of a separate, central component for several of sub-sensorsystems 10, 20, or even for all of sub-sensor systems 10, 20, for datafusion device 30 results in the advantage that this central data fusiondevice may be efficiently designed with more computing power, by whichoverall space may be saved and, at the same time, the availablecomputing power may be increased. Moreover, an interconnectioncomplexity may be reduced in this way, since several or all of thedirect data lines between sub-sensor systems 10, 20 may be dispensedwith.

If a radar sensor system 100 is designed including four sub-sensorsystems 10, 20, for example, and if each sub-sensor system 10, 20 is tobe able to use direct data links with each of the other sub-sensorsystems 10, 20, so that a processing unit of each sub-sensor system 10,20 may in each case fuse its own sensor data with the sensor data of allother sub-sensor systems 10, 20 in the normal operation, a total of sixdirect data lines thus become necessary between sub-sensor systems 10,20. In the case of N sub-sensor systems 10, 20, the number of necessarydirect data links between all sub-sensor systems 10, 20 is thusaccordingly N*(N−1)/2.

This is to be compared to the case in which all sub-sensor systems 10,20 in each case only communicate with a central data fusion device 30.Only N data lines are required for this purpose, namely one between eachsub-sensor system 10, 20 and data fusion device 30. In the case of Nsub-sensor systems, thus only N data lines are required.

One advantage of specific embodiments including direct data linesbetween all sub-sensor systems 10, 20, however, is that these specificembodiments have a particularly high redundancy, and the one, centraldata fusion device 30 (which may be integrated into control device 50,but does not have to be) does not represent a shared error source.

As was already mentioned, a preferably permanent communication, howeverat least a regular communication, between the individual sub-sensorsystems 10, 20 is desirable to be able to fuse the sensor data at apreferably low signal level, in particular, a raw data-near level.

Data fusion device 30 is, in particular, designed to fuse the sensordata generated by sub-sensor systems 10, 20 at a raw data level or at aspectra level. In other words, in particular, either the raw sensor datathemselves may be fused (raw data level), or complex signals or spectramay be ascertained, which are then fused with one another (spectralevel).

Ideally, the fusion takes place at the raw data level, which, however,necessitates a high performance of the data lines, for example usingseveral Gbps or a lot of memory, these two approaches beingcomparatively complex. To reduce this complexity, a communicationbetween sub-sensor systems 10, 20 of between one and 1000 Mbps, inparticular, between 200 and 800 Mbps, particularly preferably between300 and 700 Mbps, may advantageously be used to fuse the sensor data atone level before a subsequent angle estimation takes place.

In each sub-sensor system 10, 20, the entire data volume of allsub-sensor systems 10, 20 is advantageously mirrored in the normaloperation, so that a high degree of redundancy also exists in thisregard.

Antenna arrays 13, 23 of sub-sensor systems 10, 20 are particularlypreferably situated with respect to one another according to at least akind of symmetry. For example, in the case of two antenna arrays 13, 23,the antenna arrays may, in particular, be situated mirror-symmetricallywith respect to an axis of mirror symmetry, for example as will beexplained hereafter with reference to FIG. 2 and FIG. 3 .

If, for example, four antenna arrays 13, 23 of the radar sensor system100 are provided, an arrangement using two axes of mirror symmetry isadvantageous, so that a high accuracy may be achieved in two spatialdimensions in the best case of the radar sensor system, and a highredundancy exists in the silent operation, to be able to compensate forfailures (caused by sub-sensor systems transferred into the silentoperation).

A point-symmetrical arrangement of several or all antenna arrays 13, 23of sub-sensor systems 10, 20 may also be advantageous. However,arrangements of antenna arrays 13, 23 of sub-sensor systems 10, 20 withrespect to one another which have no symmetry, but which are nested, forexample, or have a pseudorandom arrangement, are also possible.

FIG. 2 shows a detail of a radar sensor system 100 according to onepossible specific embodiment of the present invention, first antennaarray 13 of first sub-sensor system 10 being designed and situatedmirror-symmetrically to second antenna array 23 of second sub-sensorsystem 20 with respect to an axis of mirror symmetry S. As is identifiedin FIG. 2 , elements illustrated to the left of axis of mirror symmetryS are part of first antenna array 13 of first sub-sensor system 10, andelements illustrated to the right of axis of mirror symmetry S are partof second antenna array 23 of second sub-sensor system 20.

The arrangement (i.e., in particular, orientation and positioning) ofantenna arrays 13, 23 with respect to one another is described hereafterbased on one example, according to which these antenna arrays 13, 23 orradar sensor system 100 are designed as part of a vehicle. In FIG. 2 ,the horizontal direction (i.e., from left to right) is to correspond tothe horizontal direction when driving a vehicle, and the verticaldirection, i.e., from top to bottom in FIG. 2 , is to correspond to avertical direction when driving the vehicle, i.e., different heightsabove the roadway. In this way, distributed arrangements of receivingantennas and/or transmitting antennas in the horizontal direction aresuitable for determining the so-called azimuth angle of objects withrespect to the vehicle. An arrangement distribution of receivingantennas and/or transmitting antennas in the vertical direction, incontrast, is suitable for determining the so-called elevation angle ofobjects with respect to the vehicle particularly precisely.

As is furthermore illustrated in FIG. 2 , each of these two antennaarrays 13, 23 includes multiple receiving antennas, collectivelyreferred to as RX, and multiple transmitting antennas, collectivelyreferred to as TX. Receiving antennas RX of both antenna arrays 13, 23are advantageously situated in parallel to one another in a line, in theexample in FIG. 2 in the horizontal direction. As was already mentioned,a particularly high resolution in the horizontal direction is providedin this way, i.e., the azimuth angle, with respect to the vehicle, ofobjects in the surroundings of the vehicle may be determinedparticularly precisely by radar sensor system 100. In the example shownin FIG. 2 , first antenna array 13 includes eight receiving antennas RX,which are designed as column antennas, for example.

In addition to receiving antennas RX, first antenna array 13 furthermoreincludes four transmitting antennas TX which, according to FIG. 2 , arealso designed as column antennas, other forms of antennas also beingpossible. As is furthermore shown in FIG. 2 , two of transmittingantennas TX in each case are advantageously oriented in such a way thatthey are situated in each case, along their column direction,collinearly with precisely one other transmitting antenna TX. The twopairs of collinearly situated transmitting antennas TX are shifted withrespect to one another in the horizontal direction, as well asadditionally also in the vertical direction. In other words, no two ofthe transmitting antennas are situated precisely identically in thevertical direction. Advantageously, it may be provided that twotransmitting antennas TX adjoining in the vertical direction in eachcase partially overlap in the vertical direction. In this way, aparticularly high resolution may be achieved in the vertical direction,so that the elevation angle of objects in the surroundings of thevehicle may be determined particularly precisely by radar sensor system100. In other words, the elevation performance of the output data ofradar sensor system 100 may be improved in this way.

As was already mentioned, first antenna array 13 and second antennaarray 23 are designed and situated mirror-symmetrically to one anotherwith respect to an axis of mirror symmetry S.

Transmitting antennas TX of each antenna array 13, 23 are in each case,in the horizontal direction, situated further away from axis of mirrorsymmetry S than the respective receiving antennas RX of thecorresponding antenna array 13, 23. Receiving antennas RX of firstantenna array 13 are not only situated in parallel to and in series withone another, but also with the equally situated receiving antennas RX ofsecond antenna array 23, so that the radar sensor system according toFIG. 2 overall includes sixteen receiving antennas RX situated inparallel to one another in a row.

The respective receiving antennas TX are also advantageously situated inthe vertical direction in such a way that none of transmitting antennasTX are situated, in the vertical direction, at the same level as any ofreceiving antennas RX. In this way, the resolution in the verticaldirection, i.e., the elevation performance of the output data, may befurther improved. It may be provided that in each case one oftransmitting antennas TX of antenna arrays 13, 23, in the verticaldirection, overlaps receiving antennas RX situated in parallel to oneanother, in particular, that a majority of the extension of thecorresponding transmitting antenna TX, in the vertical direction,overlaps a majority of the extension of receiving antenna RX. It mayfurthermore be provided that transmitting antenna TX, which verticallyadjoins transmitting antenna TX overlapping receiving antenna RX, issituated in such a way that it directly adjoins receiving antennas RX inthe vertical direction, but is spaced apart therefrom in the horizontaldirection.

It is clearly shown from the examples of FIG. 2 that, if one of the twosub-sensor systems 10, 20 is transferred from the normal operation intothe silent operation, the respective remaining sub-sensor system 10, 20makes it possible for the output data of the radar sensor system to beprovided with unchanged resolution in the vertical direction, and withreduced resolution, for example cut in half, in the horizontaldirection.

The specific embodiment shown in FIG. 2 is thus, in particular, suitablefor radar sensor systems 100 in which in particular the elevationperformance is also significant during the emergency operation of radarsensor system 100. Instead, the radar sensor system may also be designedincluding two sub-sensor systems 10, 20 whose antenna arrays 13, 23 aredesigned and situated mirror-symmetrically with respect to an axis ofmirror symmetry S, this axis of mirror symmetry S extending in thehorizontal direction. In this case, radar sensor system 100 would thusbe particularly well-suited for providing a consistent azimuthperformance, while the elevation performance would decrease during theemergency operation in accordance with the number of sub-sensor systems10, 20 transferred into a silent operation.

It is apparent from what was stated above that a radar sensor system 100including four or sixteen, or another number divisible by four of,sub-sensor systems 10, 20 is advantageous, since such a radar sensorsystem may include antenna arrays 13, 23 which are situatedmirror-symmetrically to one another, both in the horizontal directionand in the vertical direction, or, expressed in more general terms,which are situated mirror-symmetrically to one another with respect totwo axes of mirror symmetry S which are perpendicular to one another.Even if one sub-sensor system were to fail, both almost the fullelevation performance as well as almost the full azimuth performancewould still be achievable with such arrangements. In contrast, a radarsensor system 100 including only two sub-sensor systems 10, 20 has theadvantage of smaller dimensioning and lesser costs.

The mirror-symmetrically identical, or at least largely similar, designof antenna arrays 13, 23 of the individual sub-sensor systems 10, 20 hasthe further advantage that, during the emergency operation of radarsensor system 100, i.e., when one or multiple sub-sensor system(s) 10,20 are transferred into the silent operation, while other sub-sensorsystems 10, 20 are still in the normal operation, the quality and/orfurther properties of the output data of radar sensor system 100 differpreferably little as a function of which sub-sensor system(s) 10, 20exactly was/were transferred into the silent operation.

The specific embodiment described based on FIG. 2 , for example, has theadvantage that, regardless of which of sub-sensor systems 10, 20 fails,the same reduction in the azimuth performance and the same change(namely none) in the elevation performance take place in each case. Thelatter is due to the fact that, for each transmitting antenna TX of eachof the two sub-sensor systems 10, 20 in FIG. 2 , in each case there isat least one transmitting antenna TX of the other of the two sub-sensorsystems 10, 20, which is situated at the same vertical height, and that,for each receiving antenna RX of each of the two sub-sensor systems 10,20 in FIG. 2 , in each case there is at least one receiving antenna RXof the other of the two sub-sensor systems 10, 20, which is situated atthe same vertical height.

FIG. 3 shows a schematic block diagram of a possible specification of anelectronics architecture of a radar sensor system 100 according to FIG.1 and FIG. 2 .

The separation of radar sensor system 100 into two sub-sensor systems10, 20 separate from one another is indicated in FIG. 3 as anessentially horizontally extending, dotted curve. Elements above thiscurve are considered part of first sub-sensor system 10, or are designedas part of first sub-sensor system 10. Elements beneath this curve areassigned to second sub-sensor system 20, or are designed as part ofsecond sub-sensor system 20.

The transmitting antennas denoted collectively as TX in FIG. 2 arecombined into blocks of four transmitting antennas in each case in theelectronics architecture according to FIG. 3 and denoted by 11 and 21.Transmitting antenna block 11 of first antenna array 13 is assigned tofirst sub-sensor system 10 and designed as part thereof. Transmittingantenna block 21 of second antenna array 23 is assigned to secondsub-sensor system 20 and designed as part thereof. It shall beunderstood that antenna arrays 13, 23 may also each include multipletransmitting antenna blocks, and/or having different numbers oftransmitting antennas TX, for example transmitting antenna blocks havingtwo transmitting antennas in each case, and the like.

The receiving antennas denoted collectively as RX in FIG. 2 are combinedinto blocks of eight receiving antennas in each case in the electronicsarchitecture according to FIG. 3 and denoted by 12 and 22. Receivingantenna block 12 of first antenna array 13 is assigned to firstsub-sensor system 10 and designed as part thereof. Receiving antennablock 22 of second antenna array 23 is assigned to second sub-sensorsystem 20 and designed as part thereof. It shall be understood thatantenna arrays 13, 23 also may each include multiple receiving antennablocks, and/or having different numbers of receiving antennas RX, forexample transmitting antenna blocks having four transmitting antennas ineach case, or having two receiving antennas in each case, or the like.

One of transmitting antenna blocks 11 and one of receiving antennablocks 12 are in each case together assigned to a respective integratedcircuit 14, 24 and/or designed as part of this integrated circuit 14,24.

Integrated circuits 14, 24 may, in particular, be monolithic microwaveintegrated circuits (MMICS). In contrast, the electronic system for alltransmitting antennas and receiving antennas is integrated, for thispurpose, on a single integrated circuit for cost reasons in manyconventional radar sensor systems, so that, in the fault case of thisintegrated circuit, all transmitting antennas and all receiving antennasare covered by a silent operation.

For example, RF modules including signal generation, transmitters,receivers having a baseband chain and/or analog-to-digital convertersand the like may advantageously be integrated into integrated circuits14, 24. The combination of transmitting and receiving antenna blocks 11,21, each including the associated integrated circuit 14, 24, may also bereferred to as radar front end.

It is also explained in FIG. 3 how clock generator 60, which was alreadyexplained with respect to FIG. 1 , provides shared clock signal 71 tointegrated circuits 14, 24.

In the specific embodiment shown in FIG. 3 , which is one variant of thespecific embodiment described according to FIG. 1 , control device 50includes a multitude of control units 15, 25, at least one of controlunits 15, 25 being assigned to each sub-sensor system for transferringthe respective sub-sensor system 10, 20 into the silent operation. As isillustrated based on FIG. 3 , a first control unit 15 is advantageouslyassigned to first sub-sensor system 10, in particular, designed as partthereof, and a second control unit 25 is assigned to second sub-sensorsystem 20, in particular, designed as part thereof.

Control units 15, 25 are preferably designed as microcontrollers. As analternative or in addition, however, control units 15, 25 may alsoapplication specific integrated circuits, FPGA or the like, or bedesigned as such.

As is furthermore illustrated based on FIG. 3 , data fusion device 30includes a direct data interface between control units 15, 25, which isused to exchange the sensor data of the individual sub-sensor systems10, 20 for their fusion. Each of control units 15, 25 is supplied with asupply voltage via a respective voltage supply unit 16, 26. Theindividual voltage supply units 16, 26 may optionally be connected withthe aid of at least one (preferably exactly one) connection plug 40 to ashared bus system, for example to a vehicle bus system, such as thefrequently used CAN bus.

The fusion of the sensor data advantageously takes place in both (or inall, if more than two sub-sensor systems 10, 20 are provided) controlunits 15, 25, so that in the best case, when both sub-sensor systems 10,20 function error free, each of control units 15, 25 is able to generateand output the same output data in terms of content. In other words, acomplete mirroring may be present within each of control units 15, 25.

In the case that one of the two sub-sensor systems 10, 20 is transferredinto the silent operation, its sensor data are no longer used for thefusion of the sensor data; in the case described based on FIG. 3 ,including exactly two sub-sensor systems 10, 20, no fusion of sensordata thus takes place any longer, and only the sensor data of sub-sensorsystem 10, 20 not transferred into the silent operation are used asoutput data and/or further processed.

FIG. 3 also illustrates that control units 15, 25 are able to output theoutput data via different systems, for example also to the shared bussystem. This may take place, for example, via CAN interfaces, Ethernetinterfaces 18, 28 and/or Flexray interfaces 19, 29.

As an alternative to the case shown by way of example in FIG. 3 ,including exactly one connection plug 40, it is also possible formultiple connection plugs, namely, in particular, in each case at leastone connection plug per sub-sensor system 10, 20, to be provided.

FIG. 4 shows a schematic flow chart to explain a method for operating aradar sensor system according to one further specific embodiment of thepresent invention. The system according to FIG. 4 is, in particular,usable for operating radar sensor system 100. In this way, the methodexplained based on FIG. 4 may be adapted according to all modificationsand refinements explained above with respect to radar sensor system 100,and vice versa.

Any reference in the following description of the method according tothe present invention is of a descriptive nature, and does notnecessarily mean that the method is limited to the use of exactly thiscomponent. Whenever reference numerals of the preceding FIGS. 1 through3 are mentioned hereafter, it shall also be understood that thisprimarily serves the explanation and is not intended to mean that themethod is limited to the use of exactly these elements.

In a step S10, sensor data are received by a first sub-sensor system 10of a radar sensor system 100, first sub-sensor system 10 including anantenna array 13 including at least one receiving antenna RX and atleast one transmitting antenna TX.

In a step S20, sensor data are received by at least one secondsub-sensor system 20 of radar sensor system 100, second sub-sensorsystem 20 including a dedicated second antenna array 23 including atleast one receiving antenna RX and at least one transmitting antenna TX.First and second sub-sensor systems 10, 20 may advantageously bedesigned in such a way, in particular, as far as the arrangement anddesign of antenna arrays 13, 23 is concerned, as was described abovewith reference to FIGS. 1 through 3 . Steps S10 and S20 may, inparticular, take place concurrently, if necessary also concurrently withfurther of the explained method steps.

In a step S30, a shared clock signal 71 is provided to sub-sensorsystems 10, 20, for example as described above with respect to clockgenerator 60. The provision S30 of clock signal 71 preferably takesplace regularly, continuously and/or over an extended time period.

In a step S40, at least one of sub-sensor systems 10, 20 is transferredfrom a normal operation into a silent operation independently of theother sub-sensor systems 10, 20, in particular, as was described abovewith respect to control device 50.

In a step S50, the sensor data exclusively of those sub-sensor systems10, 20 which are in the normal operation are fused with one another forgenerating output data, in particular as was described above withrespect to data fusion device 30.

In a step S60, the generated output data are output, for example to aconnection plug 40, as was described above, for example to a connectionplug 40 designed for the connection to a vehicle. The generated outputdata may also be output in another manner to a vehicle, such aswirelessly.

It shall be understood that the described method is not limited to radarsensor systems including exactly two sub-sensor systems 10, 20, but maybe applied just as well to radar sensor systems 100 including more thantwo sub-sensor systems 10, 20, as was also already described in detailabove.

The method preferably also includes a step S70, in which at least onesub-sensor system 10, 20, which was transferred into the silentoperation, is transferred back into the normal operation. Steps S40 oftransferring into the silent operation and S70 of transferring into thenormal operation may each be part of sub-steps, in which sensor data ofsub-sensor systems 10, 20 are evaluated, and it is determined, based onthe sensor data, whether the respective sub-sensor system 10, 20 is tobe transferred into the normal operation, to continue to be operated inthe normal operation, to be transferred into the silent operation thesilent operation.

Although the present invention has been described above based onpreferred exemplary embodiments, it is not limited thereto, but ismodifiable in a variety of ways. The present invention may in particularbe changed or modified in multiple ways without departing from the coreof the present invention.

What is claimed is:
 1. A radar sensor system, comprising: a clockgenerator to provide a shared clock signal; a plurality of sub-sensorsystems including at least one first sub-sensor system and a secondsub-sensor system, each of the sub-sensor systems being configured togenerate sensor data, each of sub-sensor systems including an antennaarray, the antenna array including at least one receiving antenna and atleast one transmitting antenna; a control device, by which each of thesub-sensor systems is independently transferrable from a normaloperation into a silent operation; and a data fusion device configuredto fuse the sensor data, using only the sub-sensor systems in the normaloperation, with one another for generating output data; wherein thefirst sub-sensor system is coupled to the control device and to the datafusion device, and wherein the second sub-sensor system is coupled tothe control device and to the data fusion device, and wherein the firstsub-sensor system and the second sub-sensor system are each coupled tothe clock generator to receive the shared clock signal, wherein when theradar sensor system is in a state in which all of sub-sensor systemsfunction error free, the sensor data of all sub-sensor systems are fusedwith one another with the data fusion device, and wherein when at leastone of the sub-sensor systems is transferred into the silent operation,the sensor data of sub-sensor systems transferred into the silentoperation are not fused with the sensor data of the other sub-sensorsystems, and wherein a plurality of the antenna arrays are situatedmirror-symmetrically with respect to at least two axes of mirrorsymmetry, so that improved accuracy is achieved in at least two spatialdimensions in the radar sensor system, and redundancy exists forcompensating for a failure.
 2. The radar sensor system as recited inclaim 1, wherein the data fusion device is configured to fuse the sensordata generated by the sub-sensor systems, at a raw data level.
 3. Theradar sensor system as recited in claim 1, wherein the data fusiondevice is configured to fuse the sensor data generated by the sub-sensorsystems at a raw data level or at a spectra level.
 4. The radar sensorsystem as recited in claim 1, wherein the control device includes amultitude of control units, at least one of the control units beingassigned to each of sub-sensor systems for transferring the respectivesub-sensor system into the silent operation.
 5. The radar sensor systemas recited in claim 4, wherein the control units are microcontrollers.6. The radar sensor system as recited in claim 4, wherein the datafusion device includes a data interface between at least two of themultitude of control units.
 7. The radar sensor system as recited inclaim 1, wherein the control device includes a central control unit forat least two of the sub-sensor systems or is made up of a centralcontrol unit for all of the sub-sensor systems.
 8. The radar sensorsystem as recited in claim 1, wherein the antenna arrays of at least twoof the sub-sensor systems are situated point-symmetrically and/oraxially symmetrically and/or rotation-symmetrically with respect to oneanother.
 9. The radar sensor system as recited in claim 1, wherein eachof the sub-sensor systems includes a dedicated independent voltagesupply unit, which is feedable electrical energy via a shared plugconnector of the radar sensor system.
 10. A method for operating a radarsensor system, the method comprising: receiving sensor data of a firstsub-sensor system of a plurality of sub-sensor systems of a radar sensorsystem; receiving sensor data of a second sub-sensor system theplurality of sub-sensor systems of the radar sensor system; providing,via a clock generator, a shared clock signal to the sub-sensor systems;transferring at least one of the sub-sensor systems from a normaloperation into a silent operation, independently of the other sub-sensorsystems; fusing, via a fusion device, the sensor data using only thosesub-sensor systems which are in the normal operation, using the sharedclock signal, for generating output data; and outputting the generatedoutput data; wherein the first sub-sensor system is coupled to thecontrol device and to the data fusion device, and wherein the secondsub-sensor system is coupled to the control device and to the datafusion device, and wherein the first sub-sensor system and the secondsub-sensor system are each coupled to the clock generator to receive theshared clock signal, wherein when the radar sensor system is in a statein which all of sub-sensor systems function error free, the sensor dataof all sub-sensor systems are fused with one another with the datafusion device, and wherein when at least one of the sub-sensor systemsis transferred into the silent operation, the sensor data of sub-sensorsystems transferred into the silent operation are not fused with thesensor data of the other sub-sensor systems, and wherein a plurality ofthe antenna arrays are situated mirror-symmetrically with respect to atleast two axes of mirror symmetry, so that improved accuracy is achievedin at least two spatial dimensions in the radar sensor system, andredundancy exists for compensating for a failure.